1. Field of the Invention
The present invention belongs to a technical field for wireless communication, and relates to a configuration for simplifying an indicator section and improving a function of displaying various signal input statuses in a multi-band receiver, by displaying the signal input statuses using a multi-colored light-emitting indicator.
2. Description of the Related Art
In radio receivers, in order to visually notifying an operator of the input of a received signal, a method of turning on an indicator on an operation panel has been often adopted, hitherto. The indicator is generally referred to as a BUSY lamp.
In multi-band receivers of a type that can receive a plurality of radio waves simultaneously, in particular, in order to indicate to which frequency band a signal has been input, indicators are provided for respective frequency bands. Then, an indicator associated with the frequency band from which a signal input has been detected is automatically turned on.
FIG. 8, for example, shows a handheld transceiver that covers a 144 MHz frequency band from 144 to 146 MHz and a 430 MHz frequency band from 430 to 440 MHz, both of which are employed by a lot of amateur radio stations. Character displays of the frequency bands are provided on a liquid crystal display section 101. In addition, indicators 102 and 103, which are mono-color LEDs, are provided at locations adjacent to the liquid crystal display section 101, which correspond to the locations where the character displays are provided.
Then, when a scan mode for the frequency of a signal input is set, a built-in PLL synthesizer or the like is operated to sweep through respective frequency bands. If the signal input has been detected, an indicator for the frequency band including the received frequency is turned on.
Accordingly, each of the indicators for the handheld transceiver is driven individually; if the signal input has been detected in the 144 MHz band, the indicator 102 is turned on. If the signal input has been detected in the 430 MHz band, the indicator 103 is turned on. If signal inputs have been detected in both of the frequency bands, both of the indicators 102 and 103 are turned on. The operator can thereby see the input status of a received signal from the illumination state of each of the indicators 102 and 103.
In the configuration described above, however, there is naturally a need to provide indicators corresponding to the number of frequency bands.
Further, as illustrated in FIG. 8, it is necessary for the indicators 102 and 103 to be provided adjacent to the liquid crystal display section 101, in view of correspondence to the character displays of the frequency bands.
For these reasons, in the handheld transceiver for which miniaturization is demanded, finding room for indicators sometimes becomes difficult. Moreover, in view of a design as well, it is not also so desirable for the liquid crystal display section to be located off the center of the front surface of the housing of the transceiver.
Further, in the transceiver in FIG. 8, there assumed to be two frequency bands for reception. However, if other frequency bands are also available for reception, the size of the liquid crystal display section is limited, so that small indicators should be aligned. Thus, in addition to the problems described above, there also arises the problem that display of the indicators is so small that it is difficult to check.
Still further, the number of wiring works for drive circuits for the respective indicators increases, so that very fine and complicated works become necessary.
On the other hand, recently, there is developed an indicator disclosed in Japanese Patent Unexamined Publication HEI7-15044, where LEDs of two or three colors of RGB (red, green, blue) are mounted on a single substrate. In this indicator, lights emitted from the respective LEDs are optically mixed, thereby enabling multi-colored display.